Nano s90

The particle size of different nanoparticles was determined by dynamic light scattering (DLS) at 90° using a Zetasizer (NanoS90, Malvern Instruments, Worcestershire, UK). A refractive index of TiO₂ equal to 2.49 and of continuous phase (ethanol) equal to 1.36 was used for measurements. The reported values corresponded to an average of 10 measurements, where each sample was measured in triplicate.

The first characterization technique involved the UV–vis spectrophotometer, as described above. Second, dynamic light scattering (DLS) was used to estimate the average particle size. The DLS system (Malvern: Zetasizer nano S-90) was configured with a refractive index of 0.135, absorption of 3.99, viscosity of 0.8872, and 25 °C temperature [21 ]. Third, transmission electron microscopy (TEM) (JEM-JEOL-2100; JEOL Ltd., Peabody, MA, USA) was used to determine particle size and morphology. A 10 µL aliquot of each AgNPs sample was deposited on 400 mesh Formvar/carbon support grids and dried in a desiccator for 24 h prior to microscopic analysis. TEM was operated at 200 kV [21 ,29 (link)]. Finally, Fourier-transform infrared spectroscopy (FTIR) was implemented to identify the presence of proteins associated with AgNPs that give them stability by determining the characteristic functional groups, with samples analyzed using a Spectrum Two^™ FT-IR spectrometer [21 ].

Propolis nanoparticles were prepared by the ultrasonication method: 0.01 g Propolis and 0.1 g Tween 80 (stabilizer) were added to conical centrifuge tubes (Life Sciences, IN, USA) containing 9.89 g distilled water. The mixture was mixed in a vortex mixer (Stuart Model SA8, Bibby Scientific, UK) for 1 min followed by sonication for 20 min using a probe-type sonicator. To avoid thermal degradation of the propolis during sonication and formulation, tubes were kept in an ice bath. The particle size distribution and polydispersity index of the propolis nanoparticles were determined by dynamic light scattering using a Zeta-sizer Nano S90 (Malvern, Worcestershire, UK) at a fixed angle of 90° with a helium-neon laser, 4 mW operating at 633 nm. The formulation was suitably diluted with distilled water and measured at 25 °C. Data were collected after 2 min of equilibration time and averaged over three measurements (Figure 1).

The SPR of the green-synthesized AuNPs was evaluated using an UV–Vis spectroscopy (UH-5300, Hitachi, Japan) device in the scanning range 400–800 nm. The AuNPs were also analyzed using a dynamic light scattering (DLS; Zetasizer Nano S90, Malvern) apparatus to determine their size distribution profile and zeta potential values. The participation of biological molecules to the synthesis of AuNPs was analyzed using a Fourier-transform infrared (FTIR; FTS 7000, Varian, Australia) spectroscopy in the scanning range 500–4000 nm. The size and shape of the green-synthesized AuNPs were analyzed using a transmission electron microscopy (TEM; JEM-3010, JEOL, Japan) instrument. Furthermore, the elemental composition of the AuNPs was examined using energy-dispersive X-ray spectroscopy (EDX).

Similar techniques to those reported by Malik et al. [24 (link)] were used to assess the particle size, zeta potential, poly dispersion index (PDI), and emulsion stability of prepared nanoemulsion. These significant parameters were calculated using the equipment of Malvern (Nano-S90, Zeta sizer, Malvern Panalytical Ltd., Enigma Business Park, Grove Wood Road, Malvern, UK). The following equation was used to determine the ratio of emulsion separation: $$\% \mathrm{R}\mathrm{E}\mathrm{S}=(1-(\frac{\mathrm{V}1-\mathrm{V}2}{\mathrm{V}1} \left)\right)\times 100$$
where RES is the ratio of emulsion separation.
V1 is the total volume of nanoemulsion.
V2 is the volume of the separate solution.
The pH, acidity (as a gram of lactic acid per liter), and viscosity (as mPa) were determined by the same methodology described by Farouk et al. [25 (link)]. The emulsion characteristics were selected to reflect the stability, efficiency, and expected biological properties [32 (link)]. Also, scanning electron microscopy (Hitachi SEM, Model S-4800, Tokyo, Japan) was utilized to examine film morphology. The samples were placed in the specimen holder using double-sided adhesive tape. After vacuum sputter coating with 10 mm of gold, the samples were scanned at 1 kV with an accelerating beam voltage [33 (link)].